As Tensions Mount, North Korea Conducts 'Large-scale Artillery Drill'

North Korea conducted a massive live-fire drill Tuesday with up to 400 artillery pieces to celebrate the 85th anniversary of the founding of the country’s army.

South Korea said it is keeping a close eye on the North's military activities.

"Our military is closely monitoring the North Korean military's movements and remains firmly prepared," a statement from the South Korean Joint Chiefs of Staff says, CNN reports.

The drill comes as tensions in the region are already heightened.

The U.S. told the rogue regime this week to stop its “destabilizing actions and rhetoric.”

"North Korea's unlawful weapons programs represents a clear, grave threat to U.S. national security," Pentagon spokesman Gary Ross said in a statement.

The entire Senate has been invited to the White House for a briefing Wednesday on the situation in North Korea. Updates will be provided by Secretary of State Rex Tillerson, Secretary of Defense Jim Mattis, Chairman of the Joint Chiefs of Staff Gen. Joseph Dunford and Director of National Intelligence Dan Coats.